Extraordinary!
One of the greatest lens I've ever used. I had the f/1,8 FD version, which was already stunning, but this new model is even better, especially wide open. And the stabilizer is a great addition. To improve this lens, I can only think about a shorter minimum focusing distance. Other than that, this lens is just perfect from every point of view, regardless of the diaphragm, the lighting or the distance of focus. Bokeh is very beautiful.
May 21, 2013

this lens makes me look brilliant
Used this lens over the past 4 months and it never ceases to amaze me. Whether I am shooting a low-light dance/music recital or a portrait of a newborn & mother, this lens beautifully portrays the intimacy of the moment I am trying to capture. Simply, this lens makes me look brilliant (which I am not).
February 29, 2012

worth the $ and the weight
I thought long and hard before purchasing this lens over one year ago. Two things were worrying me...the weight and the cost. I need not have worried.
There is no doubt that this lens will become the one to go to when the very best in quality is the goal. There is a reason it is heavy....it has a lot of superb, the best Canon can make, glass. An f/2 allows almost twice the amount of light an f/2.8 allows and this makes for a super fast lens that can be used in low light situations without a second thought. While the lens is heavy, I have used it with great success, hand held, in air shows where people using 400 and 500mm lenses were using tripods and missing all the shots because there is no tripod or monopod that can be as free as a hand held. It has IS and that makes it so much more hand holdable even if the light is only mediocre, since it is such a superfast lens. Furthermore, with a lens as fast as this, action photography is a joy. Portraits? that is the strength of this lens. The dreamy background blur of the lens will spoil you and makes for extraordinary portrait shots.
I have the 70-200mm f/2.8L IS II as well and between these two lenses I am in lens heaven. The Canon 1 or 5DM2 are perfect for these lenses.
If you are on the fense for the f/2...go for it...you only live once and those photo ops don't come but once in a lifetime.
December 8, 2010

Wonderful, expensive lens
I own the 70-200mm MkII so buying this seemed like overkill but it is worth it if you can afford it.
Fantastic images with gorgeous bokeh. Heavy but you can handhold it for quick shoots. Monopod is your best friend. Focusing is super fast. Surprisingly little 'hunting' for focus. Low light focusing good so far.
I use this for nature and outdoor and indoor sports. For indoor sports or anything where you have motion and low light, this is your lens. I can dial in nice fast exposure times and even stop it down a bit to increase DOF when desired. This is what the lens was made for, and it excels here. Superb. Superlatives are overused, but for image quality and fast optics, this lens is indeed superb.
The IS on this is lens is the best of all I've used, and I've owned many. It comes as close to freezing' the lens in place as one could imagine.
Lend hood is a bit akward, the silver knob assembly that attaches the lens doesn't have the sturdy 'feel' as other lenses, and the knob is big enough to get you wondering that this could have been designed some other way that was without knob.
A lens cap to fit over the lens hood or front element would be nice for a lens this price. The lens has to have the lend hood reversed to fit into the case, so while out of case, even with hood on, there's nothing to protect the lens.
Carrying case is wonderful and sturdy, not sure how sturdy the lock is.
Tripod attachment will leave some shaking their heads. Can be removed but you have to remove four allen screws. I can imagine some ending up holding the lens by the attachment.
The lens can rotate within the tripod ring with 90 degree detents. Great feature for quickly switching from portrait and landscape and back.
The price of the lens will be the deciding factor. You get what you pay for with this lens.
June 24, 2010